I. Field of the Invention
The present invention relates generally to fasteners and, more particularly, to a fastener for a machine table having at least one T-slot.
II. Description of the Prior Art
There are many types of machining tables, such as those used with vertical mills, drill presses and the like, which have a work supporting surface on which the work is positioned. In addition, a plurality of inverted T-shaped slots are formed in the table so that the leg or narrower portion of the slot is opened to the work supporting surface while the cross bar or wider portion of the T-slot is positioned below the surface of the table.
In order to clamp the work to the table, it has been the previous practice to slide T bolts in from the end of the slot on the table and to a position adjacent the work. These previously known T bolts are dimensioned so that, although the T bolts can longitudinally slide along the slot, they cannot rotate within the slot. Consequently, with the T bolt positioned adjacent the work, a clamp or other fastener is secured to the upwardly extending end of the T bolt by a nut or other conventional fastener. Since the T bolt cannot rotate within the slot, the nut and clamp can be tightened as desired.
A primary disadvantage of these previously known T bolts used for clamping the work to the table is that it is not possible to insert a T bolt in between two T bolts or other items that are already secured to the work table. Such an additional T bolt is often required when an additional clamping is desired. Consequently, when this has occurred, it is necessary to unclamp the work, install the additional T bolt, and then reclamp the work. This previous procedure, of course, is time consuming and therefore costly.
A still further disadvantage of these previously known devices is that frequently the T bolt installed in the table is too short. When this occurs, a shaft extension is typically attached to the T bolt but such extensions are relatively expensive and cumbersome to install.
In one previously known device, a T nut is positioned within the slot and a stud is thereafter screwed into the T nut. While this eliminates the need for stud extensions, it is still not possible to insert a T nut in between two T nuts or other items secured to the table thus requiring disassembly of the setup.